Electric switch



NOV. 11, 1930. w z w 1,781,260

ELECTRIC SWITCH Filed May 11, 1928 '2 Sheets-Sheet 1 K5. WEN z LAW-3K!INVENTOR.

BYdQW/Q ZXZWL Min ATTORNEY -'NO 1930. K. E. WENZLAWSKI 1,781,260

ELECTRIC SWITCH Filed May 11, 1928 2 Sheets-Sheet 2 FIG. 5

ICE. WEN ZLA NSKI INVENTOR.

[Al ATTORNEY latented Nov. 11, 1930 PATENT OFFICE KARL EMILJi'llillflIZLAVVSKI, F GALVESTON, TEXAS ELECTRIC SWITCH Applicationfiled May 11, 1928. Serial No. 277,030.

My invention relates to electric switches for closing electric light orpower circuits.

t is particularly adapted for use in light circuits in buildings.

My device is designed to prevent danger in case of a short circuit inthe lighting circuit of a building. It is a more or less commonoccurrence when a fuse is blown out in the lighting circuit due tooverload, or to lightening, or other causes for the attendant in chargeof the building to substitute a new fuse'in place of the blown out oneand again close the circuit. Sometimes a proper fuse is not availableand coins, or nails, or pieces of wire are substituted for the fuse. Ifit happens that there is a short circuit in the building, there is thendanger of tire where the short circuit occurs.

It is an object in my invention to provide a switch for the control ofbuilding circuits or" this kind wherein provision is made to prevent theclosing of the switch when there is a short circuit in the building.

The invention consists inthe provision of an electrically operateddevice which willbe actuated to move into the path of the switch andprevent its closing where the resistance of the lighting circuithas beencut out by means of the short circuit.

Referring to the drawing herewith, Fig. 1 is a diagrammatic plan view ofa swtich emboc ying my invention. Fig. 2is an elevation of the stop armwhereby the switch is pre vented from closing, parts of the apparatusbeing removed for greater clearness. Fig. 3 is a detailed view of theelectromagnet and the operating arm whereby the stop mechanism isoperated.

I contemplate the use of my invention with the ordinary type of twoblade knife switch used in the lighting circuit of houses and otherbuildings. I have shown a switch employing two blades 1 and 2, hinged toterminals 3 and 4 respectively, the free ends of said blades beingconnected by an insulating member 5 having a handle 6. On the forwardside of the handle is a short arm 3? projecting into the path of a stopmember which will be later described.

The switch is mounted upon a base in the usual manner. The main lightcircuit 8 is connected through fuses 9 to the posts 10 audit) and itwill be seen that there are two posts 10 and 10 connected with thecontact members 11in which the blades 1 and 2 of the switch engage whenin closed. position.

The circuit from the post 10 is connected at 12 to a transformer 13 bymeans of which the voltage is materially reduced. The opposite post 10is connected by a wire 14 to the terminal 12 through the transformer.

The circuit from the transformer is carried through a wire 15 at oneside to a spring arm 16, the shape of which is best shown in Fig. 2. Itextends upwardly and has a curved contact member 17 at its upper endwhich extends in to the path of the blade 2 of the switch and contactstherewith when the blade is being moved to or from its closed position.

The other wire 17 of the auxiliary circuit is connected through anelectromagnet 18 to a post 19 at the terminal 3 of the house circuit. 7The electromagnet 18 is of ordinary construction and is adapted to movea arm 20. Said spring arm is mounted upon a post 21 on the inner side ofthe base 7 and is connected through an arm 23 of magnetic material whichextends forwardly of the base and is connected at its forward end to alink 2:2. This is a pivotal connection and the lower end of said link 22is pivotally'connected at 23 with the arm 24: of a bell crank lever 25,pivotally supported upon a pin 26 mounted upon a block 27 on the base.The upper arm 28 or" the bell crank lever extends normally upward andhas a wide notch or recess 29 therein, the sides of said notch beingbeveled outwardly at 30. This arm is intended to act as a stop to engagethe arm 87 upon the handle as previously noted.

In the operation of this device the auxiliary circuit is regulated bythe transformer 13 to be of such small voltage that when the lightcircuit through the wires 31 is connected in the usual manner throughthe resistance of the lights the current will be of insuilicientstrength to actuate the electromagnet l8. lVhen, however, the lightingcircuit is grounded in some manner the resistance of spring theauxiliary current will be suflicient to actuate the magnet to move thestop member. 7 Thus when there is a short circuit formed in the lightingcircuit 31 and a fuse has been blown out the operator may replace thefuse and attempt to close the switch. If a short circuit still remainsin the house circuit the current through the magnet in the auxiliarycircuit will be of sufiicient value to energize the magnet to move thearm 23 downwardly. Thisc will, through link 22, move the arm 25 ahctthrow the stop member 28 into position directly beneath the arm 37 uponthe handle and -prevent its closing. It is to be noted that theauxiliary circuitis not closed to energize the magnet until the blade 2of the switch contacts with the member 16. This will throw thestopmemberiinto position and hold it in that'position until the stop arm37engages therewith. It will hence be impossible to close the switch untilthe short circuit in the house lighting circuit has been repaired. I, vThe advantage of this arrangement will be obvious to those skilled inthe art. The danger from fire through short circuits in a building willbe practically eliminated. 1 9 Having thus described my invention, whata'ed'claim as new is: i 1 a 1. A safety syy-itch omprising a two bladeswitch adapted ttrcojnnectthe two.w1r es or a main light circuit to twoterminals of a house lighting circuit, in combination with anauxiliarycircuit from said light wires, a transformer in said auxiliary circuit,a resilient contactpositioned in the path of movement of one of saidswitch blades, connected with one of the'wires of said auxiliarycircuit, the other through an ele'ctromagnet to the terminal of thehouse 'circuit'remote from the said re Y silient contact member, andmeans actuated by said electromagnet when said'switch contacts withsaidresilient contact to prevent short circuit on the house circuit.

. 2. A safety'switchincluding atwo blade switch adaptedto connect thewires of a main incombination with an auxiliary circuit ofcomparativelysmall voltage, said auxiliary circuithaving one terminalthereof forming a wiping contact with one blade of said other terminalofsaid auxiliary circuit connecting to the termmal of the other blade ofsaid switch,- an electromagnet in said auxiliary circuit, and meansactuated by said .60 electromagnet to moveinto thepath of said switchand prevent its closing when there is ashort circuit in said circuit.

y 3. A safety switch including atwo blade switch adaptedtoconnectthewires of a main circuitto the'terminals of a house-lighting thelights is cut out so that the strength of of said auxiliary wires beingconnected the closing of said switch when there is a circuit to theterminals of a lighting circuit switch whensaid blade is partlyopened,the

circuit in combination with an auxiliary circuitof comparatively smallvoltage said auxiliary circuit having one terminal thereof forming awiping contact with one blade of said switch when said blade is partlyopened, the other terminal of said auxiliary circuit connecting to theterminal of the'other blade of said switch, an electromagnet in saidauxiliary circuit, and an arm operated by said electromagnet, a hingedstop member, and'a' said arm whereby said stop member may be moved intothe path of said switch and prevent its closing,

.4. A safety switch for use in a house lighting circuit, including anauxiliary circuit of '75 7 connection between said stop member andcomparatively small voltage, connected in said house circuit, saidauxiliary circuit having one terminal positioned to engage a blade ofsaid switchwhen said switch is moving to closed position, anelectromagnet in said auxiliary circuit, and a stop arm operated by saidmagnet to move into the path of said switch when there is a shortcircuit in said house circuit, to prevent the closing of said switch.

5. A safety switch for use in a'house lighting circuit, includinganauxiliary circuit of comparatively small voltage, connected in saidcircuit, sai'dauxiliary circuit having one terminal positioned to engagea blade of said switch when said switch is moving to closed position, anelectromagnet in said auxiliary circuit, and an arm operated by saidelectromagnet when said house circuit is short circuited and a stopmember moved by the operation ofsaid arm into thepath of said switch toprevent its closing. I Y Y.

6. A safety switch for use in a house lighting circuit, including anauxiliary circuit of comparatively smallrvoltage, connected in saidhouse circuit, said auxiliarycircuit'having one terminal positioned toengage a blade of said switch when; said switch is moving to closedposition, an electrically operated device in said auxiliary circuitadaptedto be energized only when the said house circuit is shortcircuited, and a stop arm adapted to be moved by said electricallyoperated'device to prevent closing of said switch when said switchengages said terminal of said auxiliary circuit. i I w In testimonywhereof I hereunto'afix my signature this 5th day of May, A. D. 1928.

KARL EMIL lVENZLAl/VSKI.

